Structural and Theoretical Study of Strontium Borophosphate Glasses Using Raman Spectroscopy and ab Initio Molecular...

Strontium borophosphate glasses of composition xSrO·(1 - x)·[0.68B₂O₃·0.32P₂O₅], 0.40 ≤ x ≤ 0.68, have been prepared by fast quenching of high-temperature melts and studied using Raman spectroscopy. In order to comprehend and confirm the obtained spectroscopic Raman data, crystalline compounds and glass-ceramics of analogous compositions were also prepared and studied. Also, ab initio molecular electronic structure theory was used to predict and confirm the experimental vibrational spectra The comparison between theoretical and experimental results showed a good overall agreement. The analysis has focused on a new detailed interpretation of the P-O-B Raman bands. Also, the analysis has revealed a divergent modification of the reported glasses near the meta-stoichiometry where the dominant species in the glass network were found to be borophosphate chains [BP₂O₉]^5-, pyrophosphate P₂O₇^4-, and orthophosphate PO₄^3- units.